Step 4:
If you still can't find your ancestor in free ships passenger lists, try ships
passenger lists and naturalization records on a pay site. See the Immigration Comparison Chart to help you decide which of the fee-based sites has the passenger lists you need to find your immigrant ancestor

IMMIGRATION & PASSENGER LISTS MAILING LISTS

Olive Tree Genealogy maintains two email discussion lists for Ships Passenger Lists for the USA and for Canada, for immigration records before passenger lists were mandatory. Here are the details of both of the new lists.

US-SHIPSLISTS-PRE1820

A mailing list for the discussion and sharing of information
regarding ship passenger lists, immigration records,
naturalization records and ships' lists substitutes for
immigration to the United States before 1820.

CAN-SHIPSLISTS-PRE1865

This is a mailing list for the discussion
and sharing of information regarding ship passenger lists,
immigration records, naturalization records and ships' lists
substitutes for immigration to Canada before 1865.